1. Field of the Invention
The present invention relates to generating a plasma using a gas composition for manufacturing a semiconductor device; more particularly, a method and an apparatus for generating a plasma using a remote process, a gas composition for generating the plasma to etch a layer, and a method for manufacturing a semiconductor device using the gas composition.
2. Description of the Related Art
Recently, semiconductor devices have been rapidly developed in order to meet various requirements of consumers and the development of information processing devices. The semiconductor devices are required to have high operation speed and large storage capacity. Thus, the semiconductor devices should be highly integrated with a design rule of below 0.15 μm. As a result, the semiconductor manufacturing processes has progressed to employing a plasma in the micro machining technology process.
Processes for generating plasma are divided into an in-situ process and a remote process, depending on the plasma type. The in-situ process generates the plasma in a chamber used for manufacturing a semiconductor device. On the other hand, the remote process inserts the plasma into the chamber after the plasma is generated outside the chamber. Utilizing the in-situ process, a substrate positioned in the chamber and the inside of the chamber may be damaged because the plasma is directly generated in the chamber. Hence, the remote process is more often employed in recent semiconductor manufacturing processes.
Examples of methods and apparatus for generating a plasma by a remote process are disclosed in Korean Laid Open Patent Publication No. 1998-79855, Korean Laid Open Patent Publication No. 2001-49697, U.S. Pat. No. 5,458,754 (issued to Sathrum el al.), U.S. Pat. No. 6,263,830 (issued to Kamarehi el al.), Japanese Laid Open Patent Publication No. 6-293980, and Japanese Laid Open Patent Publication No. 8-323873.
U.S. Pat. No. 5,458,754 discloses a method for generating a plasma by utilizing a magnetic field. U.S. Pat. No. 6,263,830 discloses a method for generating a plasma by applying microwaves. Whether employing the magnetic field or the microwave, the generation efficiency of the plasma can be improved by controlling the motion of the plasma when the plasma is generated.
FIG. 1 is a schematic view illustrating an apparatus for generating a plasma by a conventional remote process using a magnetic field.
Referring to FIG. 1, a plasma generating apparatus 1 has a tube 11 in which a gas flows. The tube 11 is divided into a first bifurcated tube 11a and a second bifurcated tube 11b at the portion of tube 11 where a source gas flows. The first and second bifurcated tubes 11a and 11b are combined at the portion of tube 11 where a plasma gas is exhausted. The source gas passes through two paths P1 and P2, and is changed into a gas having a plasma state.
The plasma generating apparatus 1 includes a magnetic field generating member 13 for generating a magnetic field to transform the gas into plasma. The magnetic field generating member 13 is disposed to enclose the first bifurcated tube 11a, but can be disposed to enclose the second bifurcated tube 11b. 
A power source 15 generates square wave high frequency alternating current to generate electric and magnetic fields to change the gas into plasma. Electrical wiring connected to the power source 15 is disposed as a coil to enclose the magnetic field generating member 13.
When the high frequency alternating current generated from the power source 15 is applied to pass through the magnetic field generating member 13, energy is applied to gas particles in the tube 11, thereby generating the plasma.
In the above-described conventional plasma generating apparatus 1, the energy induced from a core portion of the magnetic field generating member 13 (the portion where the coil is positioned) is transferred to the first bifurcated tube 11a of the tube 11. An induction electric field is formed at path P1. Path P2 serves as a secondary winding.
The gas flows through the two paths P1 and P2. The electric field directly generated from the power source 15 is applied to one path P1 of the two paths P1 and P2, while the induction electric field induced from the electric field of the power source 15 by the coil is applied to the other path P2. Thus, some energy is transferred to the gas in the second bifurcated tube 11b. 
When the induction electric field is employed, the energy cannot be sufficiently applied to the gas particles in the tube 11 due to power loss. Thus, the generation efficiency of the plasma may be reduced. To enhance the generation efficiency of the plasma, a large amount of gas can be used in the plasma generating apparatus. However, the manufacturing cost may greatly increase when the plasma generating apparatus consumes the gas on a massive scale.
Though a perfluorocarbon based gas is usually employed for manufacturing a semiconductor device and is chemically stable, the perfluorocarbon-based gas is a gas that may increase the green house effect. Hence, the exhaustion quantity of the perfluorocarbon-based gas should be reduced when the perfluorocarbon-based gas is employed for manufacturing the semiconductor device. Various methods, having no effect on the productivity of the semiconductor device, have been developed in order to reduce the exhaustion quantity of the perfluorocarbon-based gas. One example is a method utilizing an NF3 gas for generating the plasma to form fluorine radicals during the process for cleaning the semiconductor device. However, NF3 gas is expensive, so the manufacturing cost of the semiconductor device may increase.